Ceramics, metals and synthetic resins, having excellent durability, heat resistance and mechanical strength are widely used in various uses such as household appliances, electronic parts, machine parts and automobile parts. Those members are sometimes used by adhering to or combining with an elastomer member having excellent flexibility for the purpose of fixing to other structural member or for the purpose of shock absorption, breakage prevention or sealing, depending on intended use, parts structure and use method.
As such an elastomer member, a styrenic thermoplastic elastomer having excellent flexibility, mechanical properties and moldability is sometimes preferably used. The styrenic thermoplastic elastomer used herein means a block copolymer having a polymer block including aromatic vinyl compound units and a polymer block including conjugated diene compound units, or a hydrogenated product thereof. However, the styrenic thermoplastic elastomer is a material having low polarity, and its adhesive force to a ceramic, a metal or the like is not sufficient, and the styrenic thermoplastic elastomer has a problem that melting adhesion is difficult as it is. For this reason, in order that a ceramic or a metal and the styrenic thermoplastic elastomer adhere to each other, a method of applying an adhesive or previously applying a primer treatment to the surface of the ceramic, metal or synthetic resin is disclosed (see Patent Documents 1 to 6).
However, the methods disclosed in Patent Documents 1 to 6 have the problems that not only steps are complicated, but productivity is decreased and production costs are increased.
To those problems, a thermoplastic polymer composition containing a styrenic thermoplastic elastomer, a modified polyolefin and a softener is disclosed (see Patent Document 7). This thermoplastic polymer composition can be adhered to a ceramic, a metal and a synthetic resin by only a heat treatment without applying an adhesive or conducting a primer treatment.
Furthermore, Patent Document 8 discloses a thermoplastic polymer composition containing a specific styrenic thermoplastic elastomer and a functional polyolefin, in which overmolding to a polar support containing polyamide is possible and compression set under high temperature is small.